#include <QApplication>
#include <QLabel>
#include <QString>

int main(int argc,char *argv[])
{
    QApplication app(argc,argv);
    QLabel* label = new QLabel();
    QString message = QString::fromStdString("hello Qt!");
    label->setText(message);
    label->show();
    app.exec();//执行应用，堵塞代码
    return 0;
}